Matplotlib中如何让坐标轴原点重合并移除y轴左侧网格线？

我用Pandas结合Matplotlib绘制图表，已经得到基础图形，但需要实现两个调整：

1. 让x轴原点与y轴原点重合（两个零点位置对齐）
2. 移除y轴左侧的网格线

原代码如下：

import pandas as pd

def plot_responses(index, y):
    index='Arsen initial'
    y=pd.Series({1: 0.8, 2: 0.8, 3: 0.59, 4: 0.54, 5: 0.86, 6: 0.54, 7: 0.97, 8: 0.69, 9: 1.39, 10: 0.95, 11: 2.12, 12: 1.95, 13: 0.99, 14: 0.76, 15: 0.82, 16: 0.63, 17: 1.09, 18: 0.9, 19: 1.0, 20: 0.84, 21: 0.71, 22: 0.71, 23: 0.59, 24: 0.58, 25: 1.66, 26: 1.48, 27: 1.71, 28: 1.69, 29: 1.98, 30: 1.22, 31: 1.09, 32: 1.41, 33: 1.11, 34: 0.83, 35: 4.11, 36: 4.81, 37: 5.28, 38: 4.87, 39: 4.66, 40: 5.1, 41: 0.61, 42: 0.58, 43: 0.74, 44: 0.43, 45: 0.69, 46: 0.43, 47: 0.62, 48: 0.2, 49: 0.77, 50: 0.93, 51: 0.56, 52: 0.77, 53: 0.91, 54: 0.55, 55: 1.15, 56: 0.53, 57: 0.62, 58: 0.42, 59: 0.55, 60: 0.41, 61: 0.67, 62: 0.5, 63: 0.72, 64: 0.53, 65: 0.77, 66: 0.68, 67: 0.65, 68: 0.42, 69: 0.59, 70: 0.3, 71: 0.8, 72: 0.54, 73: 0.61, 74: 0.77, 75: 0.8, 76: 0.37, 77: 1.21, 78: 0.73, 79: 0.81, 80: 0.8, 81: 0.45, 82: 0.43})
    values_for_5 = []
    values_for_30 = []
    for i in range(1, y.size + 1):
        if i % 2 == 0:
            values_for_5.append(y[i])
        else:
            values_for_30.append(y[i])
    sample_no_for_5 = [i for i in range(1, len(y), 2)]
    sample_no_for_30 = [i + 1 for i in range(1, len(y), 2)]
    fig = plt.figure(figsize=(10, 10))
    ax = fig.add_subplot(1, 1, 1)
    ax.spines['left'].set_position('zero')
    ax.plot(sample_no_for_5, values_for_5, 'yo')
    ax.plot(sample_no_for_30, values_for_30, 'bo')
    plt.xlabel('Numarul mostrei', fontsize=15)
    plt.ylabel(index, fontsize=15)
    plt.title('Continutul de ' + str(index.replace(' initial', '')) + ' din gudronul acid netratat')
    for i in range(len(values_for_30)):
        ax.text(sample_no_for_5[i], values_for_5[i], '5')
        ax.text(sample_no_for_30[i], values_for_30[i], '30')
    plt.xticks(range(0, y.size, 5))
    ax.grid()
    plt.savefig(str(index.replace('initial', '').strip()) + '.jpg')
    plt.show()

修改后的完整代码 #

import pandas as pd
import matplotlib.pyplot as plt  # 补充缺失的matplotlib导入

def plot_responses(index, y):
    index='Arsen initial'
    y=pd.Series({1: 0.8, 2: 0.8, 3: 0.59, 4: 0.54, 5: 0.86, 6: 0.54, 7: 0.97, 8: 0.69, 9: 1.39, 10: 0.95, 11: 2.12, 12: 1.95, 13: 0.99, 14: 0.76, 15: 0.82, 16: 0.63, 17: 1.09, 18: 0.9, 19: 1.0, 20: 0.84, 21: 0.71, 22: 0.71, 23: 0.59, 24: 0.58, 25: 1.66, 26: 1.48, 27: 1.71, 28: 1.69, 29: 1.98, 30: 1.22, 31: 1.09, 32: 1.41, 33: 1.11, 34: 0.83, 35: 4.11, 36: 4.81, 37: 5.28, 38: 4.87, 39: 4.66, 40: 5.1, 41: 0.61, 42: 0.58, 43: 0.74, 44: 0.43, 45: 0.69, 46: 0.43, 47: 0.62, 48: 0.2, 49: 0.77, 50: 0.93, 51: 0.56, 52: 0.77, 53: 0.91, 54: 0.55, 55: 1.15, 56: 0.53, 57: 0.62, 58: 0.42, 59: 0.55, 60: 0.41, 61: 0.67, 62: 0.5, 63: 0.72, 64: 0.53, 65: 0.77, 66: 0.68, 67: 0.65, 68: 0.42, 69: 0.59, 70: 0.3, 71: 0.8, 72: 0.54, 73: 0.61, 74: 0.77, 75: 0.8, 76: 0.37, 77: 1.21, 78: 0.73, 79: 0.81, 80: 0.8, 81: 0.45, 82: 0.43})
    values_for_5 = []
    values_for_30 = []
    for i in range(1, y.size + 1):
        if i % 2 == 0:
            values_for_5.append(y[i])
        else:
            values_for_30.append(y[i])
    sample_no_for_5 = [i for i in range(1, len(y), 2)]
    sample_no_for_30 = [i + 1 for i in range(1, len(y), 2)]
    fig = plt.figure(figsize=(10, 10))
    ax = fig.add_subplot(1, 1, 1)
    
    # 实现需求1：x轴原点与y轴原点重合
    ax.spines['left'].set_position('zero')  # 将y轴移至x=0位置
    ax.spines['bottom'].set_position('zero')  # 将x轴移至y=0位置
    # 隐藏多余边框，优化视觉效果
    ax.spines['right'].set_visible(False)
    ax.spines['top'].set_visible(False)
    # 确保x轴0刻度显示在视图内
    ax.set_xlim(left=0)
    
    ax.plot(sample_no_for_5, values_for_5, 'yo')
    ax.plot(sample_no_for_30, values_for_30, 'bo')
    plt.xlabel('Numarul mostrei', fontsize=15)
    plt.ylabel(index, fontsize=15)
    plt.title('Continutul de ' + str(index.replace(' initial', '')) + ' din gudronul acid netratat')
    for i in range(len(values_for_30)):
        ax.text(sample_no_for_5[i], values_for_5[i], '5')
        ax.text(sample_no_for_30[i], values_for_30[i], '30')
    plt.xticks(range(0, y.size, 5))
    
    # 实现需求2：移除y轴左侧网格线，仅保留x轴方向网格
    ax.grid(axis='x')
    
    plt.savefig(str(index.replace('initial', '').strip()) + '.jpg')
    plt.show()

关键修改说明 #

1. 实现双原点重合 #

• 原代码仅移动了y轴到x=0位置，新增ax.spines['bottom'].set_position('zero')将x轴移至y=0位置，实现两个原点对齐。
• 隐藏右侧和顶部边框，避免多余线条干扰图表主体。
• 添加ax.set_xlim(left=0)确保x轴的0刻度处于可视范围，保证原点位置正常显示。

2. 移除y轴左侧网格线 #

• 原代码ax.grid()会绘制所有方向的网格线，修改为ax.grid(axis='x')后，仅保留x轴方向的水平网格线，自然移除了y轴左侧的垂直网格线。

内容的提问来源于stack exchange，提问作者Bogdan Doicin